Researchers aid fight against coastal erosion

Researchers at Ohio State University, USA, have developed a new method of mapping the ocean currents that cause coastal erosion, which is cheaper and more practical than the alternatives currently available.

The new method involves a single video camera and software that uses foam from breaking waves to track the complex flow of water near the shore. The system has been used to film a 500 metre stretch of a beach’s surf zone, where ocean waves break and circulate against the shore, analysing the image of the water, focussing on the white, foamy patches of bubbles left after breaking waves had passed. Based on where the foam moved, the software calculated the speed and direction of the currents, and matched data taken by a traditional system to within 10%.

“If we could better measure and predict water circulation patterns, we could learn more about erosion, as well as other near-shore phenomena such as rip currents and undertow,” said Thomas Lippmann, research scientist in Ohio State’s Department of Civil and Environmental Engineering and the Byrd Polar Research Centre.

The sensors currently used by scientists make individual measurements at single locations, whereas water circulation patterns tend to vary over much larger areas, said Lippmann. This means that scientists need to install dozens of sensors to study a single section of beach, with each sensor costing anywhere between $5,000 and $20,000. An array of 30 sensors could cost as much as $1.2 million – an amount beyond the reach of all but a few research programmes worldwide, said Lippmann. The new system would eventually cost no more than $100,000.

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